JP2000297761A - Micro pump and chemical analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the leakage angle of a liquid relative to a discharge face at the instant when the liquid is discharged and separated from a discharge port and improve the shutoff property of the liquid immediately after the discharge is completed by forming a groove around the discharge port on the discharge face including the discharge port of the liquid on a discharge nozzle section. SOLUTION: A discharge nozzle 101 is provided at the center section of a nozzle substrate 100. The discharge nozzle 101 is constituted of a discharge port 110 discharging or dripping a liquid and a bank 113 formed as a projection 113, and an inlet 111 is provided on the liquid entering side of the nozzle substrate 100. A groove 112 is formed around the discharge port 110. A half or above of the thickness of the nozzle substrate 100 is enough for the depth of the groove 111 in consideration of the strength of the discharge nozzle 101, and the reduction of discharge precision and stains around the discharge port 110 caused by the sticking of the liquid can be prevented. Discharge resolution and discharge stability can be improved without requiring periodic disassembling and cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micropump for discharging liquid, and more particularly to a micropump for discharging several microliters to several hundred microliters per second, and a concentration of a substance dissolved in a sample liquid using the micropump. To a chemical analyzer for quantifying

[0002]

2. Description of the Related Art A conventional micropump is disclosed in
No. 73856 is disclosed. This micropump has a structure in which a pump structure manufactured by silicon micromachining is sandwiched between glass substrates, and this structure is incorporated in a pump case. The pump case is provided with a pump case input through-hole that is a liquid supply port to the pump, and a pump case output through-hole that is a liquid discharge port from the pump. Is provided with a protrusion.

[0003]

The purpose of using a micropump in a quantitative discharge device for discharging a liquid, an inspection device for analyzing and analyzing by a chemical reaction between a discharged liquid and a sample, an analyzer, and the like is as follows. And the ejection accuracy is improved. Japanese Patent Application Laid-Open No. 6-173856 also aims at practical use as a precision fluid control device for medical use, analysis, and quantitative discharge of liquid. On the other hand, the main factors that affect the discharge accuracy include the drive accuracy of the pump driver, the volume of the pump chamber, and the presence / absence of liquid remaining after discharge. Among them, the influence of the remaining liquid droplets is small when the liquid can be sucked after the discharge. However, since the suction operation cannot be performed with the structure of the micropump described in the above publication, it is necessary to eliminate the remaining liquid droplets by controlling the driving of the pump driver and the structure of the discharge port. The micropump disclosed in the above publication is provided with a projection around the pump case output through-hole. However, in this structure, droplets may remain after the ejection is stopped, and when the droplets remain, the droplets are ejected together with the next ejection droplet, and the quantitativeness may decrease.

[0004] It is an object of the present invention to provide a liquid discharger having a good liquid drainage property even in a micropump in which suction control is difficult, and high discharge accuracy even when there is no remaining liquid droplet after liquid discharge and the amount of liquid discharged is very small. And a chemical analysis device using the same.

[0005]

In order to achieve the above object, a discharge nozzle portion of a micropump for discharging or dropping a liquid is formed with a groove around a discharge port on a discharge surface including a liquid discharge port. Alternatively, the liquid ejection port is formed so as to protrude from the ejection surface. This increases the wetting angle of the liquid with respect to the discharge surface at the moment when the liquid is discharged and separates from the discharge port, so that the liquid is easily cut immediately after the discharge is completed. Further, if a groove is formed from the periphery of the liquid discharge port toward the outside of the discharge nozzle, or a thin tube is provided, and a liquid absorbing means is provided at the outer end of the groove or the thin tube, the discharge port Droplets adhering to the surroundings are removed from the discharge surface by capillary action, and can be absorbed by the water absorber. Thus, it is possible to reduce the ejection accuracy due to the adhesion of the liquid and prevent dirt around the ejection port. Further, when a fluorine resin layer or a compound layer containing fluorine is formed on the discharge nozzle, the surface tension of the discharge surface is reduced, the wetting angle of the liquid with respect to the discharge surface is further increased, and the liquid is more easily drained. At this time, when the flow velocity at which the liquid is discharged is Y and the area of the discharge port is X, the flow velocity Y and the area X are Y ≧ (0.884 + 4.82 · exp (− (X−0.0
If the design of the micropump and the discharge nozzle and the control of the discharge amount are performed so as to satisfy 188) /0.0287), the liquid can be drained.

Also, a reaction container holder for holding a plurality of reaction containers for holding a sample, a plurality of reagent containers for respectively holding various reagents to be added to the sample in the reaction container, The macro pump described above, which is a micro pump for absorbing a fixed amount of a reagent and injecting it dropwise into the reaction container, and a micro pump of a chemical analyzer including a measuring device for measuring physical properties of the sample after the reagent is added. By using, the liquid is easily drained, there is no remaining liquid droplet after the liquid is discharged, and high discharge accuracy can be obtained even when the amount of the discharged liquid is small.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a discharge nozzle for a micropump and a chemical analyzer according to the present invention will be described with reference to the drawings.

First, the configuration of the chemical analyzer of the present invention will be described with reference to FIG. FIG. 1A shows a chemical analyzer 1.
1 is a plan view, and FIG. 1B is a front view thereof.

At the upper part of the chemical analyzer 11, a sample holder 22 for holding the test tubes 21 containing the samples 20 arranged in a circular shape in a plane is provided. A sample pipetter 31 for sucking the sample 22 in the test tube 21 is provided beside the sample holder 22. The sample pipetter 31 sucks a sample from the test tube 21 and holds the sample inside, a three-dimensional drive mechanism 33 that moves the nozzle 32 up and down and turns, and sucks and discharges the sample into the nozzle 32. A pump (not shown) is provided. The sample holder 22 includes a plurality of test tubes 2.
The rotary drive mechanism 23 is driven to rotate the sample pipets 1 immediately below the nozzles 32 of the sample pipettor 31 one by one.

[0010] A reaction disk 42 is provided adjacent to the sample holder 22 so as to sandwich the sample pipettor 31. The reaction disk 42 includes a plurality of reaction vessels 41.
Are arranged in a circular shape in a plane, and are sequentially rotated to move the reaction vessel 41 to the other lowered position of the nozzle 32 of the sample pipettor 31. The lower half of each reaction vessel 41 is immersed in a constant temperature bath 43 through which constant temperature water flows. In order to sequentially move the reaction vessel 41 to the lower position of the nozzle 32 of the sample pipettor 31, the reaction disk 4
2 is provided with a reaction disk rotation drive mechanism 44.
Above the outer peripheral edge of the reaction disk 42, a reaction vessel cleaning mechanism 71 and a spectrometer 81 are provided in this order.

Next, the configuration of the reagent supply section 51 will be described. The reagent supply unit 51 is roughly divided into a plurality of reagent containers 5.
2. It is composed of four parts: a reagent holder 53 for holding a reagent container 52, a micropump 54, and a reagent holder rotation drive mechanism 55. The reagent holder has a structure for holding the reagent container 52 on the circumference around the central axis. The same number of membrane pumps 5 as the number of reagent containers 52 held
4 is provided at the bottom of the reagent holder 53. A connection hole is provided on the bottom surface of the reagent container 52, and the reagent holder 5
By strongly pressing the bottom of the micro pump 3 toward the bottom, it is connected to the suction hole of the micro pump 54. Also,
A discharge nozzle is provided on the surface of the micro pump 54 opposite to the suction port, and a discharge port formed in the discharge nozzle is provided vertically downward. Here, the discharge nozzle is a generic name of several discharge nozzles described later.

FIG. 2 is a schematic sectional view of the micropump 54. The micro pump includes a nozzle substrate 100, an outlet valve substrate 200, a liquid transfer chamber substrate 300, and a diaphragm substrate 40.
0, and each substrate is fixed. However, the outlet valve 201 of the outlet valve substrate 200 and the liquid transfer chamber substrate 3
The inlet valve 301 of FIG. 00 and the diaphragm 401 of the diaphragm substrate 400 are not fixed because they are parts operated by liquid feeding. The liquid is sent from a swing means (not shown) connected to the diaphragm 401, for example, a piezo element, an electromagnetic actuator, a shape memory alloy actuator, or the like. In the embodiment of the present invention, a piezo element actuator is used.

This micropump includes a diaphragm 40
By driving the actuator connected to 1, the outlet valve is closed and the inlet valve 301 is opened by changing the capacity of the liquid sending chamber to a direction in which the capacity of the liquid sending chamber is increased, and a liquid such as a reagent is sucked into the liquid sending chamber from the suction hole. . Next, the actuator is operated to compress the liquid sending chamber, thereby closing the inlet valve 301 and opening the outlet valve 201 to discharge the liquid from the discharge port.
As described above, the amount of liquid to be discharged is controlled by the number of times the diaphragm 401 is driven.

FIG. 3 is a sectional view of an embodiment of the nozzle substrate according to the present invention.

A discharge nozzle 1 is provided at the center of the nozzle substrate 100.
01 is provided. The discharge nozzle 101 includes a discharge port 110 from which a liquid is discharged or dropped and a bank 1 serving as a protrusion.
13 Further, the nozzle substrate 100 is also provided with an inlet 111 on the side where the liquid enters. A groove 112 is formed around the discharge port 110. In this embodiment, the groove 1
12 has a depth of 100 micrometers and a width of 770 micrometers, but is not limited thereto. The depth of the groove 112 is determined in consideration of the strength of the discharge nozzle 101.
It is sufficient that the thickness is at least half of the thickness of the substrate. Since the material of the nozzle substrate 100 is silicon and the processing is micromachining, the discharge port 110 and the entrance 111 are square.

At the time of joining the nozzle substrate 100 and the pump body (not shown), a joining jig (not shown) may come into contact with the discharge surface 114 and damage the bank 113 as a projection. , The bank 113 is closer to the inlet 1 than the discharge surface 114.
It has a structure retracted to the 11 side. The nozzle substrate 100 shown here has a rectangular plate shape, but may have a disk shape, an elliptical plate shape, or other shapes.

In the above-described embodiment, the height of the bank of the discharge nozzle 101 is set lower than the surface of the substrate. However, the height of the bank 113 is set to the same height as the surface of the substrate, and a bonding jig is set around the nozzle substrate. By providing a concave portion, it is possible to prevent the joining jig from contacting the bank 113. By setting the end surface of the bank 113 to be in the same plane as the substrate surface, it is possible to omit the micromachining process for retreating the bank 113.

FIG. 4 shows a nozzle substrate 1 according to another embodiment of the present invention.
00 is shown.

The discharge nozzle 101 has a configuration different from the previous embodiment in that it protrudes from the substrate surface 114. Therefore, the structure is simplified, and the number of micromachining processes can be reduced. When the nozzle substrate 100 and the pump main body are joined together, a concave portion is provided in the periphery of the substrate so that the bank 113 does not hit the joining jig, although not shown in the figure.

FIG. 5 shows a nozzle substrate according to still another embodiment of the present invention. The difference from FIG.
Is formed in a conical shape. For this reason, the discharge port 110, the groove 112, and the bank 113 are formed by machining without using micromachining. The material was made of stainless steel, hard vinyl chloride, and three kinds of ethylene tetrafluoride, but the material is not limited to these, and resins such as polypropylene, ABS resin and polypropylene sulfide, metals other than stainless steel, glass, ceramics, etc. May be. However, in the case of mechanical processing, mass production is inferior to micromachining due to fine processing, but the cost of equipment is cheaper than micromachining and it does not require special micromachining technology In some cases, the whole may be useful.

Also, as in FIG. 4, the discharge nozzle 101 can be formed so as to protrude from the substrate surface. The formation of the discharge nozzle 101 can be performed by machining. FIG.
As described above, it is necessary to provide a concave portion in the peripheral portion of the substrate so as not to damage the discharge nozzle 101 upon joining with another substrate.

FIG. 6 shows a nozzle substrate according to still another embodiment of the present invention.

A groove 112 provided around the discharge port 110
A long groove 134 is formed outward from the nozzle substrate 100. A water absorber 135 is provided at an end of the long groove 134. For this reason, even when the liquid discharged or dropped around the discharge port 110 remains, the droplet is absorbed by the absorber 135 along the long groove 134 due to the capillary action, and
No liquid remains around 0, and it is possible to prevent a decrease in accuracy of the discharged liquid. If the liquid remains around the discharge port 110, dirt is generated by drying, and this dirt can be prevented. The material of the nozzle substrate 100 was silicon, and was processed by silicon micromachining.

FIG. 7 shows a nozzle substrate according to still another embodiment of the present invention.

The difference between FIG. 6 and FIG.
The point is that a long groove 134 is extended to the discharge nozzle without providing a groove around 01. Note that an absorber 135 is provided at an end of the long groove 134. The material of the nozzle substrate 100 was silicon, and was processed by silicon micromachining.

FIG. 8 shows still another embodiment of the Japanese invention.

The difference between this embodiment and FIG. 6 is that the discharge nozzle 1
01 has a conical shape, and a thin tube 146 communicating with the groove 112 provided around the discharge nozzle 101 is provided.
A water absorbing body 145 is attached to the other end of 46. As a result, it is possible to prevent a decrease in ejection accuracy and the attachment of dirt.

The ejection nozzle 10 described above is used.
In No. 1, the surface was coated with a fluorine resin or a compound containing fluorine. As a result, the wettability of the liquid to be discharged or dropped onto the discharge nozzle is reduced, that is, the liquid is repelled, so that the liquid is easily cut off when the discharge is stopped, and the discharge accuracy is reduced and contamination is prevented. The effect becomes larger. However, regarding the discharge nozzle 101 of FIGS. 6 to 8, it is preferable that the coating of the fluorine resin or the compound containing fluorine is not provided on the inner side of the long groove 134 or the inner surface of the thin tube 146, so that the liquid wettability is better. Therefore, this is a more desirable configuration because the capillary phenomenon easily occurs.

The method of coating a fluorine resin or a compound containing fluorine is as follows.
This is a method of drying in a furnace heated at 0 ° C. to 230 ° C. for 5 minutes or more. Further, instead of dipping, spray coating or brush coating may be used. However, regarding the film thickness control, the immersion method was the best and could be controlled within an error range of 10 to 50 nanometers. The film thickness error in the case of spray coating is 50 to 20
It was as large as 0 nanometer. In the case of brushing, the thickness error was 400 to 600 nanometers.

FIGS. 9 and 10 show the results of an experiment for examining the ejection characteristics when ejecting a liquid from the ejection port provided in the ejection nozzle.

The method of sending liquid to the discharge nozzle is as follows: when a syringe pump is connected to the inlet side of the discharge nozzle to send liquid;
This is a case in which a discharge nozzle is joined to a micropump and liquid is sent. Ion-exchanged water or an alkaline reagent was used as the discharge liquid. The alkaline reagent has a surface tension of about 30 d
yn / cm. Therefore, the surface tension is about 72 dy.
Since the wettability is better than that of n / cm water, the liquid drainage after the discharge is stopped is reduced.

FIG. 9 shows the results of a discharge test performed by a syringe pump using a discharge nozzle with a discharge port area of 0.116 mm ^2, which has no bank and is coated with a fluororesin.
Assuming that the speed at which the liquid exits the discharge port is the discharge speed, if the discharge speed is smaller than 0.5 m / s, the liquid will be discharged from the liquid droplet 6 in FIG.
When the liquid accumulates in the discharge port as shown at 11 and reaches a certain size, the liquid drops by gravity and surface tension. In this case, the dropping of the liquid is intermittent, not ejection. 0.5-1.0m
/ S range, there is no accumulation of liquid at the discharge port,
After the ejection is stopped, the remaining droplets remain. When the ejection speed is higher than 1.1 m / s, there is no remaining droplet, the ejection is good, and the liquid drainage is good. From the above results, it was found that the higher the discharge speed, the better the liquid drainage property, and that there is a limit discharge speed when there is no remaining droplet. Hereinafter, the above-described limit discharge speed without remaining droplets is referred to as a minimum discharge speed without remaining droplets.

FIG. 10 is an experimental result showing the minimum value of the discharge speed without the remaining droplet when the discharge port area is variously changed. The conditions of the discharge nozzles are those in which the discharge ports are round or square, without or with a bank, liquid transfer by a syringe pump or liquid transfer by a micro pump, and mixed with each other. Fluororesin coating was applied. The discharge liquid is an alkaline reagent. From the experimental results, the relationship between the discharge port area of the discharge nozzle without a bank or the discharge nozzle with a bank and the minimum discharge speed without residual liquid is as follows.
When the fluororesin coating was applied, it was confirmed that substantially the same result was obtained even when the discharge port shape and the liquid sending method were different. That is, the knowledge that the ejection characteristics depend on the presence or absence of the bank was obtained. FIG. 10 shows the results obtained by approximating the data points of the discharge nozzle with the fluorine resin coating without the bank and the discharge nozzle with the fluorine resin coating with the bank by an exponential decreasing function. Since the vertical axis is the minimum value of the discharge speed without the residual liquid, the range in which the discharge can be performed without the residual liquid is represented by Formula 1. The constants Y0, X0, A, and t are shown in Table 1. In addition, the discharge nozzle with a fluororesin coating showed the minimum value and the average value of the data.

[0034]

(Equation 1)

[0035]

[Table 1]

The bank 11 shown in FIGS. 3 to 9 according to the present invention.
When the fluororesin coating is applied to the discharge nozzles 101a to 101g having the nozzles 3 and 123, the discharge equation satisfying the relational expression when the minimum value constant is substituted into Equation 1 in Table 1 is taken into consideration in consideration of the variation range of the data. The conditions of the outlet area and the minimum value of the discharge speed without residual liquid are effective for the liquid exhaustion of the discharge port 110.

FIGS. 11 and 12 are cross-sectional views for explaining a state where the residual liquid after discharge adheres to the discharge nozzle 101 portion. FIG. 11 shows a discharge nozzle 101 coated with a fluororesin.
FIG. 12 shows the case without the coating. When coated, the remaining droplets become liquid droplets 611, but when there is no coating, they become liquid films 612. The same effect can be obtained by using a fluorine-containing compound for a fluorine resin. The portion where the fluororesin layer 160 is provided always includes the groove 112, that is, the outside of the bank 113, and preferably, the discharge surface 114 is also coated. Of course, the entire surface of the discharge nozzle 101 may be coated.

FIG. 13 is a view schematically showing a silicon machining procedure for manufacturing the discharge nozzle 101 on the nozzle substrate 100 of the present invention. A semiconductor process technique is used.

As shown in FIG. 5A, silicon dioxide is formed on a silicon substrate 501 by thermal oxidation, and then a resist is applied. Exposure, development, removal of the resist, and partial removal of the silicon dioxide layer 504 form a silicon dioxide layer 502. I do.

(B) The silicon substrate 501 is anisotropically etched and dug down from the silicon exposed surface 504 to form a recess 50.
5 is formed, and the silicon dioxide layer 502 is removed.

(C) Next, a silicon dioxide layer 510 is formed by a semiconductor process.

(D) Further thereon, a silicon dioxide layer 5
A 20 or trisilicon tetranitride layer 520 is formed.

(E) Next, when anisotropic etching is performed to dig down from the silicon exposed surface 525, a shape like a concave portion 535 is formed.

(F) Thereafter, the silicon dioxide layer 520 or the tri-silicon tetranitride layer 520 formed on the upper portion is removed, and digging is continued by anisotropic etching so that the recess 534 and the recess 535 communicate with each other. Let it.

(G) Finally, the silicon dioxide layer 510 is removed to complete a silicon substrate 500g.

As described above, in the above description, the micro pump is formed by forming and joining the nozzle substrate as a separate substrate from the outlet valve substrate. However, the discharge nozzle is formed on the outlet valve substrate as a matter of course. Thus, the number of parts of the micropump can be reduced, and the pump itself can be made thinner.

[0047]

According to the present invention, a small amount of reagent can be easily controlled and a simple nozzle is provided without wasting reagents, hardly requiring a cleaning solution, and not requiring periodic disassembly and cleaning. Further, it is possible to provide a chemical analyzer having a high discharge resolution and a high discharge stability and having a chemical resistant nozzle and a pump, and to propose a manufacturing method thereof.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a chemical analyzer according to the present invention.

FIG. 2 is a schematic sectional view of the micropump of the present invention.

FIG. 3 is a view of a nozzle substrate of the micropump of the present invention.

FIG. 4 is a view showing an embodiment of another nozzle substrate of the present invention.

FIG. 5 is a view showing an embodiment of another nozzle substrate of the present invention.

FIG. 6 is a view showing an embodiment of another nozzle substrate of the present invention.

FIG. 7 is a view showing an embodiment of another nozzle substrate of the present invention.

FIG. 8 is a view showing an embodiment of another nozzle substrate of the present invention.

FIG. 9 is a view showing a discharge speed condition at which a discharge nozzle can run out of liquid.

FIG. 10 is a view showing a liquid-out characteristic of a discharge nozzle.

FIG. 11 is a cross-sectional view of the nozzle portion showing a state after the reagent has been discharged when the coating is performed on the discharge nozzle portion.

FIG. 12 is a cross-sectional view of the nozzle portion showing a state after the reagent is discharged when the coating is not applied to the discharge nozzle.

FIG. 13 is a diagram illustrating a method for manufacturing a discharge nozzle according to the present invention.

[Explanation of symbols]

11: Upper part of the apparatus main body, 12: Front part of the apparatus main body, 21 ...
Test tube, 22: sample holder, 31: sample pipettor, 32: nozzle, 41: reaction vessel, 43: constant temperature bath,
52: Reagent container, 53: Reagent holder, 54: Micro pump, 542: Discharge hole, 100: Nozzle substrate, 110
... discharge port, 113 ... embankment, 112 ... groove, 134 ... long groove,
135 ... water absorber, 502 ... silicon dioxide layer, 160 ...
Fluororesin layer.

Continued on the front page (72) Inventor Yasuhiko Sasaki 502, Kachimachi, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. (72) Inventor Takao Terayama 882 Ma, Hitachinaka-shi, Ibaraki Pref.Hitachi, Ltd.Measurement Instruments Division, Hitachi, Ltd. ) Inventor Yoshishige Endo 502 Jincho-cho, Tsuchiura-shi, Ibaraki F-term in Machinery Research Laboratories, Hitachi, Ltd. 2G058 ED12 ED23 ED24 3H077 AA08 CC02 CC09 DD06 EE16 FF12

Claims (5)

[Claims] 1. A diaphragm substrate having a diaphragm formed thereon for imparting displacement to a liquid feed chamber, and a liquid feed chamber substrate joined to the diaphragm substrate to form an inlet valve and an opening to a liquid feed chamber and an outlet side. And a micropump comprising an outlet valve substrate provided with an outlet valve, a nozzle substrate provided with a discharge nozzle joined to the outlet valve substrate and discharging a liquid discharged from the outlet valve to the outside, A micropump characterized by forming a groove around a discharge nozzle. 2. A diaphragm substrate having a diaphragm formed thereon for imparting displacement to a liquid feed chamber, and a liquid feed chamber substrate joined to the diaphragm substrate to form an inlet valve and an opening to the liquid feed chamber and an outlet side. And a micropump comprising an outlet valve substrate provided with an outlet valve, a nozzle substrate provided with a discharge nozzle joined to the outlet valve substrate and discharging a liquid discharged from the outlet valve to the outside, A micropump wherein a discharge nozzle is formed so as to protrude from a surface of the nozzle substrate. 3. A diaphragm substrate provided with a diaphragm for displacing a liquid supply chamber, and a liquid supply chamber substrate joined to the diaphragm substrate to form an inlet valve and an opening to the liquid supply chamber and an outlet side. And a micropump comprising an outlet valve substrate provided with an outlet valve, a nozzle substrate provided with a discharge nozzle joined to the outlet valve substrate and discharging a liquid discharged from the outlet valve to the outside, A micropump characterized in that a groove or a tube is provided from the periphery of the discharge nozzle toward the outside of the discharge nozzle. 4. The micropump according to claim 1, wherein a fluororesin layer or a fluorine-containing compound layer is formed on an outermost layer of the discharge nozzle portion. 5. A reaction container holder for holding a plurality of reaction containers for holding a sample, a plurality of reagent containers for respectively holding various reagents to be added to the sample in the reaction container,
A pump attached to the lower part of the reagent container, which absorbs a predetermined amount of reagent and instills it into the reaction container, and a chemical analyzer including a measuring device for measuring physical properties of the sample after the reagent is added, The pump includes a pump main body, and a discharge nozzle joined to a front surface of the pump main body and having a plate-shaped discharge port connected to an outlet of the pump main body. A chemical analyzer wherein a groove is formed around an outlet.